Definitions of sounding:

• noun:   the act of measuring depth of water (usually with a sounding line)
• noun:   a measure of the depth of water taken by sounding
• adjective:   having volume or depth

  Example: "Sounding brass and a tinkling cymbal"

• adjective:   making or having a sound as specified; used as a combining form

  Example: "Harsh-sounding"

• adjective:   appearing to be as specified; usually used as combining forms

  Example: "Fine-sounding phrases"